US20110271754A1 - Liquid Level Transducer with Heating Unit - Google Patents
Liquid Level Transducer with Heating Unit Download PDFInfo
- Publication number
- US20110271754A1 US20110271754A1 US13/100,975 US201113100975A US2011271754A1 US 20110271754 A1 US20110271754 A1 US 20110271754A1 US 201113100975 A US201113100975 A US 201113100975A US 2011271754 A1 US2011271754 A1 US 2011271754A1
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- United States
- Prior art keywords
- tube
- heating
- liquid level
- container
- mounting head
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/30—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats
- G01F23/64—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats of the free float type without mechanical transmission elements
- G01F23/72—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats of the free float type without mechanical transmission elements using magnetically actuated indicating means
- G01F23/74—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats of the free float type without mechanical transmission elements using magnetically actuated indicating means for sensing changes in level only at discrete points
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/10—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/1406—Storage means for substances, e.g. tanks or reservoirs
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/148—Arrangement of sensors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
- F01N2900/1806—Properties of reducing agent or dosing system
- F01N2900/1814—Tank level
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
Definitions
- This invention relates to liquid level transducers, and more particularly to liquid level transducers having heating arrangements for heating the surrounding material to be measured.
- Transducers for measuring liquid level are often used in vehicles, industrial equipment as well as other mobile and stationary systems and components.
- the electrical output of such transducers changes in response to a change in the liquid level being measured and is typically in the form of a change in resistance, capacitance, current flow, magnetic field, and frequency.
- These types of transducers may include variable capacitors or resistors, optical components, Hall Effect sensors, strain gauges, ultrasonic devices, reed switch arrays, and so on.
- DEF engine coolant and diesel exhaust fluid
- SCR Selective Catalytic Reduction
- a liquid level transducer is often associated with the tank to indicate a level of the DEF to an operator or other observer.
- the DEF can freeze when subjected to low temperature conditions and thus cannot be accurately measured or extracted from the tank until it is changed to a liquid state.
- a transducer for determining the level of contents within a container wherein the contents are subjected to solidifying below a freezing temperature.
- the transducer includes: a mounting head adapted for connection to the container; a liquid level sensor adapted to extend into the container from the mounting head; and a spiral-shaped heating unit comprising a first elongate tube extending through the mounting head.
- the first elongate tube is formed with at least one coil that surrounds at least a portion of the liquid level sensor and is adapted to circulate heating fluid therein to thereby heat the contents of the container at least in the vicinity of the liquid level sensor.
- a transducer for determining liquid level within a container includes: a mounting head adapted for connection to the container; a liquid level sensor adapted for extending into the container from the mounting head; and a heating tube extending through the mounting head.
- the heating tube has: first and second upright segments connected via a first lower bend; a third upright segment connected to the second upright segment via an upper bend; and a fourth upright segment connected to the third upright segment via a second lower bend.
- the first and fourth upright segments are adapted for fluid connection to a fluent heating source for heating the contents of the container.
- a transducer for determining the level of contents within a container wherein the contents are subjected to solidifying below a freezing temperature.
- the transducer includes: a mounting head adapted for connection to the container; a liquid level sensor adapted for extending into the container from the mounting head; and a heating unit extending through the mounting head and into the container.
- the heating unit has an outer tube and an inner tube extending inside and along a length of the outer tube.
- the outer and inner tubes are in fluid communication such that heating fluid is adapted to flow from one of the outer and inner tubes to the other of the outer and inner tubes to thereby heat the contents of the container.
- FIG. 1 is a front isometric view of a liquid level transducer with a heat transfer unit connected to a tank in accordance with on embodiment of the present invention
- FIG. 2 is a side elevational view thereof
- FIG. 3 is a view similar to FIG. 1 with the tank removed;
- FIG. 4 is a view similar to FIG. 3 with a mounting plate removed to reveal the details of an upper portion of the liquid level transducer;
- FIG. 5 is top isometric view of the liquid level transducer
- FIG. 6 is a view similar to FIG. 5 with a housing portion removed to reveal the details of the upper portion of the liquid level transducer;
- FIG. 7 is a view similar to FIG. 6 with a transfer block removed to reveal more details of an end portion of the liquid level transducer;
- FIG. 8 is an enlarged bottom isometric view of the liquid level transducer
- FIG. 9 is a bottom perspective view of the liquid level transducer
- FIG. 10 is a front elevational view of a liquid level transducer with a heat transfer unit in accordance with a further embodiment of the present invention.
- FIG. 11 is a rear elevational view thereof
- FIG. 12 is a top perspective view thereof
- FIG. 13 is a side perspective view of an upper portion of the liquid level transducer of FIG. 10 ;
- FIG. 14 is a left side elevational view of an upper portion thereof
- FIG. 15 is a right side elevational view of an upper portion thereof.
- FIG. 16 is a front elevational view of a lower portion of the liquid level transducer of FIG. 10 ;
- FIG. 17 is left side elevational view of the lower portion thereof.
- FIG. 18 is a top schematic view of a tank and the heat transfer unit of FIG. 10 for comparing the size of the opening with the heat transfer unit;
- FIG. 19 is a front isometric view of a liquid level transducer with a heat transfer unit connected to a tank in accordance with a further embodiment of the present invention.
- FIG. 20 is a sectional view of a heat transfer unit in accordance with yet another embodiment of the invention.
- FIG. 21 is a sectional view thereof taken along line 21 - 21 of FIG. 20 ;
- FIG. 22 is a front elevational view of a liquid level transducer with heat transfer unit in accordance with a further embodiment of the invention.
- FIG. 23 is an enlarged view of a portion of the heat transfer unit of FIG. 22 .
- the liquid level transducer 10 preferably extends into a container 11 , such as a fuel tank, oil reservoir, radiator, brake fluid chamber, or any other container for holding and/or transporting a liquid (not shown).
- a container 11 such as a fuel tank, oil reservoir, radiator, brake fluid chamber, or any other container for holding and/or transporting a liquid (not shown).
- the transducer 10 is particularly useful for liquids that have a tendency to freeze at lower temperatures, such as diesel exhaust fluids (DEF) in a NOx emissions control system.
- DEF diesel exhaust fluids
- Such fluids can include, but are not limited to, water, urea, ammonia, and combinations thereof.
- the transducer 10 preferably includes a mounting head 14 , an elongate sensing probe 12 extending through the mounting head 14 and downwardly therefrom, a heating unit 16 extending through the mounting head 14 and bending around the sensing probe 12 , and a fluid supply tube 18 extending through the mounting head 14 and along a substantial length of the heating unit 16 .
- the sensing probe 12 preferably senses liquid level in a linear direction and, in accordance with one preferred embodiment of the invention, includes an outer sensor tube 22 with an upper end 24 that extends through the mounting head 14 and a lower end 26 with a support block 28 .
- a float 30 is preferably cylindrically-shaped and includes a central bore 32 (shown in FIG. 8 ) that is sized to receive the sensor tube 22 so that the float slides freely therealong.
- the support block 28 preferably holds the heating unit 16 , the lower end 26 of the sensor tube 22 , and preferably serves as a lower resting position for the float 30 in the event of a very low level or empty tank condition.
- a printed circuit board (PCB—not shown) is positioned within the sensor tube 22 and preferably extends along a substantial length thereof.
- a plurality of reed switches (not shown) are located along the length of the PCB. The reed switches are responsive to one or more magnets (not shown) located in the float 30 for creating a liquid level signal in a well-known manner as the float rides along the sensor tube 22 in response to a change in liquid level within the tank.
- insulating material such as heat-shrink tubing, potting material, and so on, is preferably located between the PCB and the sensor tube 22 to insulate and protect the reed switches and other components against shock, vibration, and other harsh conditions to which the transducer 10 may be exposed.
- Potting material may also be located at the upper end 24 of the sensor tube 22 to provide strain relief for the electrical wires 40 ( FIGS. 3 , 4 , 6 and 7 ) that extend between the PCB and an electrical connector 42 , as well as vibration protection for the PCB and its interface with the wires.
- the sensor tube 22 can also contain other sensors besides liquid level, in particular temperature, which would provide information to the heating circuit for controlling circulation of the heating fluid through the heating unit 16 .
- Wiring connections and any circuitry required for the sensing is preferably located within the sensor tube and inside a sealed compartment within the mounting head 14 and sensor tube connection.
- linear-type liquid level measurement sensors including but not limited to, capacitance, heated wire, ultrasonic, optical, and so on, as well as non-linear-type sensors such as resistance-type pivoting float arms.
- the heating unit 16 preferably includes a single piece or length of tube that is bent into the tortuous shape as shown and includes a first upper segment 44 that extends generally horizontally and is fluidly connected to a fluent heat source (not shown) such as such as engine coolant, oil, hot exhaust gases and so on, in order to provide constant or selective intermittent circulation of heating fluid to warm the contents of the tank 11 ( FIG. 1 ).
- a first upright leg 46 extends generally vertically downwardly from the first upper segment 44 and is connected to a second generally vertically extending upright leg 48 via a first lower generally U-shaped bend 50 extending therebetween.
- a third generally vertically extending upright leg 52 is in turn connected to the second leg via an upper generally U-shaped bend 54 .
- a fourth generally vertically extending upright leg 56 is in turn connected to the third leg 52 via a second lower generally U-shaped bend 58 that is vertically higher than the first bend 50 .
- the first and second lower U-shaped bends 50 , 58 are preferably connected to the support block 28 for providing stability at the lower end of the transducer 10 .
- the fourth leg 56 is in turn fluidly connected to a second generally horizontally extending upper segment 60 , which is in turn fluidly connected to the fluent heat source.
- the sensor tube 22 and fluid supply tube 18 are preferably securely connected to the heating tube 16 and to each other via clips 62 and 64 .
- the parts can be connected together through any well-known connection means, including but not limited to, adhesives, welding, other types of mechanical fastening, and so on.
- a substantial portion of the fluid supply tube 18 preferably extends adjacent to the first leg 46 of the heating tube 16 .
- the supply tube 18 can alternatively be located adjacent to the fourth leg 56 .
- the supply tube 18 preferably includes a generally horizontally extending upper segment 68 that extends through the mounting head 14 .
- the supply tube 18 is adapted for connection to a pump (not shown) or the like in a well-known manner for delivering liquid from the tank 11 to a remote location.
- the supply tube 18 preferably extends to an empty level position inside the tank adjacent to the lower U-shaped bends 50 , 58 .
- a filter (not shown) can be located at the lower end of the supply tube 18 inside the tank.
- the tortuous shape of the heating tube 16 is particularly advantageous since the four upright legs 46 , 48 , 52 and 56 increase the amount of heating tube surface area installed in the tank and create a space or volume 66 within the tank 11 that is more quickly heated than the surrounding area.
- the heating tube carries warm fluid, such as engine coolant
- the heat transferring from the heating tube is used to thaw or prevent freezing of the tank contents surrounding the sensor as well as the supply tube 18 located within the space 66 .
- Increasing the amount of surface area of the heating tube 16 increases the amount of heat transfer in a given amount of time. This reduces the potential for freezing of the tank contents in the area of the sensor and supply tubes at lower temperatures and causes quicker thawing of the contents at a given temperature than if the heating tube 16 were constructed with less segments.
- the mounting head 14 preferably includes a cover 70 connected to a mounting plate 72 which is in turn connected to the tank 11 ( FIG. 1 ).
- the cover 70 together with the mounting plate 72 create a hollow interior through which the segments 44 , 60 of the heating tube 16 and the segment 68 of the supply tube 18 preferably extend.
- a transfer block 74 is secured to the mounting plate 72 and includes passages for receiving the heating tube and supply tube segments, as well as an opening for receiving the electrical wires 40 and connector 42 .
- a valve assembly 76 extends into the transfer block 74 and is in fluid communication with the segment 44 of the heating tube and the fluent heating source (not shown).
- the liquid level transducer 110 preferably extends into a container (not shown), such as a fuel tank, oil reservoir, radiator, brake fluid chamber, or any other container for holding and/or transporting a liquid (not shown).
- a container such as a fuel tank, oil reservoir, radiator, brake fluid chamber, or any other container for holding and/or transporting a liquid (not shown).
- the transducer 110 is particularly useful for liquids that have a tendency to freeze at lower temperatures, such as diesel exhaust fluids (DEF) in a NOX emissions control system.
- DEF diesel exhaust fluids
- Such fluids can include, but are not limited to, water, urea, ammonia, and combinations thereof.
- the transducer 110 preferably includes a mounting head 114 , an elongate sensing probe 112 extending through the mounting head 114 and downwardly therefrom, a helically-shaped heating unit 116 extending through the mounting head 114 and spiraling around the sensing probe 112 , a fluid supply tube 118 extending through the mounting head 114 and along a substantial length of the heating unit 116 , and a liquid return tube 120 extending through the mounting head 114 .
- the sensing probe 112 preferably senses liquid level in a linear direction and, in accordance with one preferred embodiment of the invention, includes an outer sensor tube 122 with an upper end 124 that extends through the mounting head 114 and a lower end 126 with a stop flange 128 .
- a float 130 is preferably cylindrically-shaped and includes a central bore 132 (shown in hidden line in FIG. 16 ) that is sized to receive the sensor tube 122 so that the float slides freely therealong.
- the stop flange 128 provides a lower resting position for the float 130 in the event of a very low level or empty tank condition.
- a printed circuit board (PCB) 134 is positioned within the sensor tube 122 and preferably extends along a substantial length thereof.
- a plurality of reed switches (not shown) are located along the length of the PCB 134 .
- the reed switches are responsive to one or more magnets (not shown) located in the float 130 for creating a liquid level signal in a well-known manner as the float rides along the sensor tube 122 in response to a change in liquid level within the tank.
- Insulating material 136 such as heat-shrink tubing, potting material, and so on, is preferably located between the PCB 134 and the sensor tube 122 to insulate and protect the reed switches and other components against shock, vibration, and other harsh conditions to which the transducer 110 may be exposed.
- Potting material 138 FIG. 13
- a potting grommet 142 is received over the PCB 134 for limiting the height of the potting material during assembly and curing.
- a cushion 133 FIG.
- the sensor tube 122 is preferably located with the sensor tube 122 and surrounds the PCB 134 below the stop flange 138 for providing further protection against vibration and undesired forces that may otherwise be present on the PCB during shipping, installation and/or operation.
- the sensor tube 122 can also contain other sensors besides liquid level, in particular temperature, which would provide information to the heating circuit for controlling circulation. Wiring connections and any circuitry required for the sensing is preferably located within the sensor tube and inside a sealed compartment above the mounting head 114 and sensor tube connection.
- linear-type liquid level measurement sensors can be used, including but not limited to, capacitance, heated wire, ultrasonic, optical, pivoting float arm, and so on, as well as non-linear-type sensors such as resistance-type pivoting float arms.
- the heating unit 116 is preferably in the form of a single, elongate tube with a first leg 144 and a second leg 146 and a generally U-shaped bend 148 extending therebetween.
- the first and second legs 144 and 146 include straight upper segments 150 and 152 , respectively, that extend through the mounting head 114 .
- the upper ends of the segments 150 , 152 are adapted for connection to supply and return conduits (not shown) of a fluent heat source, such as such as engine coolant, oil, hot exhaust gases and so on, in order to provide constant and/or intermittent circulation of heating fluid to warm the contents of the tank (not shown).
- the sensor tube 122 is preferably securely connected to the heating tube 116 .
- the parts are preferably welded together.
- connection means including but not limited to, adhesives, ultrasonic welding, mechanical fastening, and so on.
- a substantial portion of the fluid supply tube 118 is preferably connected to the first leg 144 of the heating tube 116 and thus spirals around the sensing probe therewith. However, it will be understood that the supply tube 118 can alternatively be connected to the second leg 146 .
- the supply tube 118 preferably includes a straight upper segment 154 that extends through the mounting head 114 .
- the supply tube 118 and return tube 120 are adapted for connection to a pump or the like in a well-known manner for delivering liquid from the tank (not shown) on which the transducer is mounted to a remote location and returning unused liquid back into the tank.
- the extension of the fluid supply and return tubes into the tank can be inside of the helical heating tube 116 or parallel on the same diameter.
- the fluid return tube does not have to extend far into the tank, but can if desired.
- the supply tube 118 preferably extends into the tank to the empty level inside the tank adjacent the U-shaped bend 148 . If desired, a filter (not shown) can be located at the lower end of the supply tube 118 inside the tank.
- the helical configuration of the heating tube 116 is especially advantageous in that the helical coil can be made larger in diameter than the mounting head 114 ( FIG. 10 ) and the opening 156 ( FIG. 18 ) in the tank wall 158 to which the transducer 110 is mounted.
- the major or outside diameter C of the heating tube 116 is larger than the diameter A of the tank opening 156 , which is in turn larger than the minor or inside diameter B of the heating tube 116 .
- the maximum major diameter C can be calculated as follows:
- the major diameter C of the heating tube 116 is approximately 7.5 inches, a significantly larger heating tube area that the contents of the tank will be exposed to over prior art solutions.
- the distance or spacing 160 between adjacent coils is preferably greater than a thickness of the tank wall 158 ( FIG. 18 ) to which the transducer 110 will be mounted so that the thickness of the tank wall at the tank opening 156 can be cleared during the installation process.
- the transducer 110 can be screwed into a tank opening 156 , preferably with the float lifted to the upper portion of the sensing tube 122 just below the mounting head 114 , with the tank opening being much smaller in diameter than the outside diameter of the coils of the helically-shaped heating tube 116 .
- the amount of heater tubing surface area installed in the tank is significantly increased.
- the heat transferring from the coil is used to thaw or prevent freezing of the tank contents surrounding the sensor as well as the supply and return tubes.
- Increasing the amount of surface area of the heater tubing increases the amount of heat transfer in a given amount of time. This reduces the potential for freezing of the tank contents in the area of the sensor and supply tubes at lower temperatures and causes quicker thawing of the contents at a given temperature than if the coils of the heating tube 116 were constructed with a smaller diameter.
- the liquid level transducer 180 preferably extends into a container 11 and preferably includes a mounting head 14 , an elongate sensing probe 12 extending through the mounting head 14 and downwardly therefrom with a float 30 movable along the length of the probe 12 as previously described, a first or inner heating unit 16 extending through the mounting head 14 and bending around the sensing probe 12 , a second or outer heating unit 116 spiraling around the inner heating unit 16 and a fluid supply tube 18 extending through the mounting head 14 and along a substantial length of the heating unit 16 .
- the inner and outer heating units are similar in construction to the heating units previously described, with the inner heating unit 16 being sized to slip through the tank opening and the outer heating unit 116 having an outer diameter, as previously described, that is larger than the tank opening so that the liquid level transducer 180 turned or twisted through the tank opening to install the transducer in the tank.
- the inner and outer heating units provide more surface area for thawing or warming the fluid to be measured at an increased rate without increasing the overall size of the liquid level transducer so that it can fit within a standard tank opening.
- the liquid level transducer 190 preferably includes a sensor tube 192 located within a heating unit which preferably includes an inner heating fluid return tube 194 which is in turn located within an outer heating fluid supply tube 196 .
- the sensor tube 192 is preferably connected to the outer supply tube 196 via a connector 198 that preferably includes a hub 200 that preferably encircles and connects to the inner return tube 194 and spokes 202 that extend radially outwardly from the hub 200 and connect to the outer supply tube 196 .
- a lower end 204 of the outer supply tube 196 preferably tapers toward the sensor tube 192 to create an internal chamber 206 that communicates with both the inner return tube and outer supply tube.
- heating fluid from a fluid source such as previously described, is directed down into the outer supply tube 196 , as shown by arrows 208 , to thereby heat the outer tube and the contents within the tank in the vicinity of the outer tube, and then up into the inner return tube 194 , as shown by arrows 210 , 212 , where it exits the transducer 190 .
- the inner tube 194 can alternatively receive heating fluid and the outer tube 196 can function as the fluid return conduit without departing from the spirit and scope of the invention.
- the inner return tube 194 and/or outer supply tube 196 can be constructed of stiff or flexible material.
- the inner tube 194 is constructed of a flexible material that is compatible to the heating fluid such as rubber, polyurethane, vinyl, and so on, while the outer tube 196 is constructed of a more rigid or stiff material such as stainless steel, aluminum, other metals, and so on.
- the inner and outer tubes can be constructed of any suitable materials without departing from the spirit and scope of the invention.
- the sensor tube 192 preferably houses a liquid level probe such as a reed-switch-type probe as previously shown and described.
- a liquid level probe such as a reed-switch-type probe as previously shown and described.
- the present invention is not limited thereto as other linear-type liquid level measurement sensors can be used, including but not limited to, capacitance, heated wire, ultrasonic, optical, and so on, as well as non-linear-type sensors such as resistance-type pivoting float arms
- the transducer 220 preferably includes a mounting head 222 , an elongate sensing probe 224 extending through the mounting head 114 and downwardly therefrom, and a helically-shaped heating unit 226 extending through the mounting head 222 and spiraling around the sensing probe 224 .
- the sensing probe 224 is preferably similar in construction to the sensing probe 112 with float 130 as previously described.
- the heating unit 226 preferably includes an inner heating fluid return tube 228 located within an outer heating fluid supply tube 230 .
- the inner tube 228 is preferably constructed of a flexible material that is compatible to the heating fluid such as rubber, polyurethane, vinyl, and so on, while the outer tube 230 is constructed of a more rigid or stiff material such as stainless steel, aluminum or other metals, so that the heating unit 226 can be shaped in a quick and easy manner during manufacture through simple bending operations.
- a lower end 231 of the outer heating unit is sealed so that the heating fluid remains in the heating unit during use.
- the heating unit 226 in this embodiment is easier to manufacture and requires less material than the spiral heating tube previously described with reference to FIGS. 10 and 19 since the heating unit does not need to spiral back up as in the previous embodiments.
- the inner tube 228 of the present embodiment can alternatively receive heating fluid and the outer tube 230 can function as the fluid return conduit without departing from the spirit and scope of the invention.
- the heating unit 226 has an outer diameter that is larger than the tank opening, as previously described with respect to FIG. 18 . In accordance with another preferred embodiment of the invention, the heating unit 226 has an outer diameter that is smaller than the tank opening so that the liquid level transducer 220 can be installed straight into the tank without the need to twist the transducer.
- Rods 232 and 234 or other support structure can extend between the mounting head 222 and a lower base member 236 to provide added support to the liquid level transducer 220 .
- connection refers to two or more parts capable of being attached together either directly or indirectly through one or more intermediate members.
- terms of orientation and/or position as may be used throughout the specification denote relative, rather than absolute orientations and/or positions.
- orientation and/or position refers to relative rather than absolute orientations and/or positions.
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- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
A transducer for determining the liquid level within a container that is subjected to at least partial solidification at or below a freezing temperature is provided. The transducer includes a mounting head adapted for connection to the container, a liquid level sensor adapted for extending into the container from the mounting head; and a heating unit extending through the mounting head. The heating unit is constructed of at least one tubular member that surrounds or encircles the liquid level sensor. Heated fluid from a fluid source is circulated through the at least one tubular member for heating the contents of the tank at least within the vicinity of the liquid level sensor. A fluid withdrawal tube can also be in close proximity to the at least one tubular member so that the contents of the tank surrounding the heating unit can be removed even when the remaining tank contents are in a frozen state.
Description
- This application claims the benefit of U.S. Provisional Application No. 61/330,969 filed on May 4, 2010, the disclosure of which is hereby incorporated by reference in its entirety.
- This invention relates to liquid level transducers, and more particularly to liquid level transducers having heating arrangements for heating the surrounding material to be measured.
- Transducers for measuring liquid level are often used in vehicles, industrial equipment as well as other mobile and stationary systems and components. The electrical output of such transducers changes in response to a change in the liquid level being measured and is typically in the form of a change in resistance, capacitance, current flow, magnetic field, and frequency. These types of transducers may include variable capacitors or resistors, optical components, Hall Effect sensors, strain gauges, ultrasonic devices, reed switch arrays, and so on.
- No matter what transducer type is used, the tank level measurement is most successful when the material being measured is in a liquid state as opposed to a semi-solid or frozen state. Although many fuels have a freezing point well below the operating temperature range of most vehicles and equipment, other fluids are subjected to freezing such as engine coolant and diesel exhaust fluid (DEF). DEF is especially problematic since it is used in vehicles equipped with Selective Catalytic Reduction (SCR) systems. DEF is a solution that typically comprises purified water and approximately 32.5 percent urea and is used to reduce nitrogen oxide (NOx) emissions from diesel-powered vehicles into nitrogen, water and carbon dioxide (CO2). The DEF is kept in a tank on the vehicle and is automatically accessed during vehicle operation to reduce emissions. A liquid level transducer is often associated with the tank to indicate a level of the DEF to an operator or other observer. Unfortunately, the DEF can freeze when subjected to low temperature conditions and thus cannot be accurately measured or extracted from the tank until it is changed to a liquid state.
- Prior art solutions have been inadequate in addressing these problems in a satisfactory manner. It would therefore be desirous to provide a heating arrangement associated with the liquid level transducer and/or liquid withdrawal or supply tubes of DEF tanks or the like so that the level of DEF can be more quickly ascertained and accessed during freezing conditions.
- In accordance with one aspect of the invention, a transducer for determining the level of contents within a container wherein the contents are subjected to solidifying below a freezing temperature is provided. The transducer includes: a mounting head adapted for connection to the container; a liquid level sensor adapted to extend into the container from the mounting head; and a spiral-shaped heating unit comprising a first elongate tube extending through the mounting head. The first elongate tube is formed with at least one coil that surrounds at least a portion of the liquid level sensor and is adapted to circulate heating fluid therein to thereby heat the contents of the container at least in the vicinity of the liquid level sensor.
- In accordance with a further aspect of the invention, a transducer for determining liquid level within a container includes: a mounting head adapted for connection to the container; a liquid level sensor adapted for extending into the container from the mounting head; and a heating tube extending through the mounting head. The heating tube has: first and second upright segments connected via a first lower bend; a third upright segment connected to the second upright segment via an upper bend; and a fourth upright segment connected to the third upright segment via a second lower bend. The first and fourth upright segments are adapted for fluid connection to a fluent heating source for heating the contents of the container.
- In accordance with yet another aspect of the invention, a transducer for determining the level of contents within a container wherein the contents are subjected to solidifying below a freezing temperature is provided. The transducer includes: a mounting head adapted for connection to the container; a liquid level sensor adapted for extending into the container from the mounting head; and a heating unit extending through the mounting head and into the container. The heating unit has an outer tube and an inner tube extending inside and along a length of the outer tube. The outer and inner tubes are in fluid communication such that heating fluid is adapted to flow from one of the outer and inner tubes to the other of the outer and inner tubes to thereby heat the contents of the container.
- The following detailed description of the preferred embodiments of the present invention will be best understood when considered in conjunction with the accompanying drawings, wherein like designations denote like elements throughout the drawings, and wherein:
-
FIG. 1 is a front isometric view of a liquid level transducer with a heat transfer unit connected to a tank in accordance with on embodiment of the present invention; -
FIG. 2 is a side elevational view thereof; -
FIG. 3 is a view similar toFIG. 1 with the tank removed; -
FIG. 4 is a view similar toFIG. 3 with a mounting plate removed to reveal the details of an upper portion of the liquid level transducer; -
FIG. 5 is top isometric view of the liquid level transducer; -
FIG. 6 is a view similar toFIG. 5 with a housing portion removed to reveal the details of the upper portion of the liquid level transducer; -
FIG. 7 is a view similar toFIG. 6 with a transfer block removed to reveal more details of an end portion of the liquid level transducer; -
FIG. 8 is an enlarged bottom isometric view of the liquid level transducer; -
FIG. 9 is a bottom perspective view of the liquid level transducer; -
FIG. 10 is a front elevational view of a liquid level transducer with a heat transfer unit in accordance with a further embodiment of the present invention; -
FIG. 11 is a rear elevational view thereof; -
FIG. 12 is a top perspective view thereof; -
FIG. 13 is a side perspective view of an upper portion of the liquid level transducer ofFIG. 10 ; -
FIG. 14 is a left side elevational view of an upper portion thereof; -
FIG. 15 is a right side elevational view of an upper portion thereof; -
FIG. 16 is a front elevational view of a lower portion of the liquid level transducer ofFIG. 10 ; -
FIG. 17 is left side elevational view of the lower portion thereof; -
FIG. 18 is a top schematic view of a tank and the heat transfer unit ofFIG. 10 for comparing the size of the opening with the heat transfer unit; -
FIG. 19 is a front isometric view of a liquid level transducer with a heat transfer unit connected to a tank in accordance with a further embodiment of the present invention; -
FIG. 20 is a sectional view of a heat transfer unit in accordance with yet another embodiment of the invention; -
FIG. 21 is a sectional view thereof taken along line 21-21 ofFIG. 20 ; -
FIG. 22 is a front elevational view of a liquid level transducer with heat transfer unit in accordance with a further embodiment of the invention; and -
FIG. 23 is an enlarged view of a portion of the heat transfer unit ofFIG. 22 . - It is noted that the drawings are intended to depict only exemplary embodiments of the invention and therefore should not be considered as limiting the scope thereof. It is further noted that the drawings are not necessarily to scale. The invention will now be described in greater detail with reference to the accompanying drawings.
- Referring now to the drawings, and to
FIGS. 1 and 2 in particular, aliquid level transducer 10 according to an exemplary embodiment of the present invention is illustrated. Theliquid level transducer 10 preferably extends into acontainer 11, such as a fuel tank, oil reservoir, radiator, brake fluid chamber, or any other container for holding and/or transporting a liquid (not shown). In accordance with one preferred application of the invention, thetransducer 10 is particularly useful for liquids that have a tendency to freeze at lower temperatures, such as diesel exhaust fluids (DEF) in a NOx emissions control system. Such fluids can include, but are not limited to, water, urea, ammonia, and combinations thereof. - With additional reference to
FIGS. 3-5 and 9, thetransducer 10 preferably includes amounting head 14, anelongate sensing probe 12 extending through themounting head 14 and downwardly therefrom, aheating unit 16 extending through themounting head 14 and bending around thesensing probe 12, and afluid supply tube 18 extending through themounting head 14 and along a substantial length of theheating unit 16. - As best shown in
FIGS. 2-4 and 6-8, thesensing probe 12 preferably senses liquid level in a linear direction and, in accordance with one preferred embodiment of the invention, includes anouter sensor tube 22 with anupper end 24 that extends through themounting head 14 and alower end 26 with asupport block 28. Afloat 30 is preferably cylindrically-shaped and includes a central bore 32 (shown inFIG. 8 ) that is sized to receive thesensor tube 22 so that the float slides freely therealong. Thesupport block 28 preferably holds theheating unit 16, thelower end 26 of thesensor tube 22, and preferably serves as a lower resting position for thefloat 30 in the event of a very low level or empty tank condition. A printed circuit board (PCB—not shown) is positioned within thesensor tube 22 and preferably extends along a substantial length thereof. A plurality of reed switches (not shown) are located along the length of the PCB. The reed switches are responsive to one or more magnets (not shown) located in thefloat 30 for creating a liquid level signal in a well-known manner as the float rides along thesensor tube 22 in response to a change in liquid level within the tank. Although not shown, insulating material, such as heat-shrink tubing, potting material, and so on, is preferably located between the PCB and thesensor tube 22 to insulate and protect the reed switches and other components against shock, vibration, and other harsh conditions to which thetransducer 10 may be exposed. Potting material (not shown) may also be located at theupper end 24 of thesensor tube 22 to provide strain relief for the electrical wires 40 (FIGS. 3 , 4, 6 and 7) that extend between the PCB and anelectrical connector 42, as well as vibration protection for the PCB and its interface with the wires. - It will be understood that the
sensor tube 22 can also contain other sensors besides liquid level, in particular temperature, which would provide information to the heating circuit for controlling circulation of the heating fluid through theheating unit 16. Wiring connections and any circuitry required for the sensing is preferably located within the sensor tube and inside a sealed compartment within the mountinghead 14 and sensor tube connection. - Although a reed-switch-type probe has been shown and described, it will be understood that the present invention is not limited thereto. It will be understood that other linear-type liquid level measurement sensors can be used, including but not limited to, capacitance, heated wire, ultrasonic, optical, and so on, as well as non-linear-type sensors such as resistance-type pivoting float arms.
- As best shown in
FIGS. 6-8 , theheating unit 16 preferably includes a single piece or length of tube that is bent into the tortuous shape as shown and includes a firstupper segment 44 that extends generally horizontally and is fluidly connected to a fluent heat source (not shown) such as such as engine coolant, oil, hot exhaust gases and so on, in order to provide constant or selective intermittent circulation of heating fluid to warm the contents of the tank 11 (FIG. 1 ). A firstupright leg 46 extends generally vertically downwardly from the firstupper segment 44 and is connected to a second generally vertically extendingupright leg 48 via a first lower generallyU-shaped bend 50 extending therebetween. A third generally vertically extendingupright leg 52 is in turn connected to the second leg via an upper generallyU-shaped bend 54. Likewise, a fourth generally vertically extendingupright leg 56 is in turn connected to thethird leg 52 via a second lower generallyU-shaped bend 58 that is vertically higher than thefirst bend 50. The first and second lower U-shaped bends 50, 58 are preferably connected to thesupport block 28 for providing stability at the lower end of thetransducer 10. Thefourth leg 56 is in turn fluidly connected to a second generally horizontally extendingupper segment 60, which is in turn fluidly connected to the fluent heat source. - In order to eliminate the need for an internal tank restraint and provide greater structural integrity for the
transducer 10, thesensor tube 22 andfluid supply tube 18 are preferably securely connected to theheating tube 16 and to each other viaclips - A substantial portion of the
fluid supply tube 18 preferably extends adjacent to thefirst leg 46 of theheating tube 16. However, it will be understood that thesupply tube 18 can alternatively be located adjacent to thefourth leg 56. Thesupply tube 18 preferably includes a generally horizontally extendingupper segment 68 that extends through the mountinghead 14. Thesupply tube 18 is adapted for connection to a pump (not shown) or the like in a well-known manner for delivering liquid from thetank 11 to a remote location. Thesupply tube 18 preferably extends to an empty level position inside the tank adjacent to the lower U-shaped bends 50, 58. If desired, a filter (not shown) can be located at the lower end of thesupply tube 18 inside the tank. - The tortuous shape of the
heating tube 16 is particularly advantageous since the fourupright legs volume 66 within thetank 11 that is more quickly heated than the surrounding area. When the heating tube carries warm fluid, such as engine coolant, the heat transferring from the heating tube is used to thaw or prevent freezing of the tank contents surrounding the sensor as well as thesupply tube 18 located within thespace 66. Increasing the amount of surface area of theheating tube 16 increases the amount of heat transfer in a given amount of time. This reduces the potential for freezing of the tank contents in the area of the sensor and supply tubes at lower temperatures and causes quicker thawing of the contents at a given temperature than if theheating tube 16 were constructed with less segments. - As shown in
FIGS. 3-6 and 9, the mountinghead 14 preferably includes acover 70 connected to a mountingplate 72 which is in turn connected to the tank 11 (FIG. 1 ). Thecover 70 together with the mountingplate 72 create a hollow interior through which thesegments heating tube 16 and thesegment 68 of thesupply tube 18 preferably extend. Atransfer block 74 is secured to the mountingplate 72 and includes passages for receiving the heating tube and supply tube segments, as well as an opening for receiving theelectrical wires 40 andconnector 42. Avalve assembly 76 extends into thetransfer block 74 and is in fluid communication with thesegment 44 of the heating tube and the fluent heating source (not shown). - Referring now to
FIGS. 10 and 11 , aliquid level transducer 110 in accordance with a further exemplary embodiment of the invention is illustrated. Theliquid level transducer 110 preferably extends into a container (not shown), such as a fuel tank, oil reservoir, radiator, brake fluid chamber, or any other container for holding and/or transporting a liquid (not shown). In accordance with one preferred application of the invention, thetransducer 110 is particularly useful for liquids that have a tendency to freeze at lower temperatures, such as diesel exhaust fluids (DEF) in a NOX emissions control system. Such fluids can include, but are not limited to, water, urea, ammonia, and combinations thereof. - With additional reference to
FIG. 12-15 , thetransducer 110 preferably includes a mountinghead 114, anelongate sensing probe 112 extending through the mountinghead 114 and downwardly therefrom, a helically-shapedheating unit 116 extending through the mountinghead 114 and spiraling around thesensing probe 112, afluid supply tube 118 extending through the mountinghead 114 and along a substantial length of theheating unit 116, and aliquid return tube 120 extending through the mountinghead 114. - As best shown in
FIGS. 10 , 11, 13, 16 and 17, thesensing probe 112 preferably senses liquid level in a linear direction and, in accordance with one preferred embodiment of the invention, includes anouter sensor tube 122 with anupper end 124 that extends through the mountinghead 114 and alower end 126 with astop flange 128. Afloat 130 is preferably cylindrically-shaped and includes a central bore 132 (shown in hidden line inFIG. 16 ) that is sized to receive thesensor tube 122 so that the float slides freely therealong. Thestop flange 128 provides a lower resting position for thefloat 130 in the event of a very low level or empty tank condition. - A printed circuit board (PCB) 134 is positioned within the
sensor tube 122 and preferably extends along a substantial length thereof. A plurality of reed switches (not shown) are located along the length of thePCB 134. The reed switches are responsive to one or more magnets (not shown) located in thefloat 130 for creating a liquid level signal in a well-known manner as the float rides along thesensor tube 122 in response to a change in liquid level within the tank. - Insulating
material 136, such as heat-shrink tubing, potting material, and so on, is preferably located between thePCB 134 and thesensor tube 122 to insulate and protect the reed switches and other components against shock, vibration, and other harsh conditions to which thetransducer 110 may be exposed. Potting material 138 (FIG. 13 ) is located at theupper end 124 of thesensor tube 122 to provide strain relief for theelectrical wires 140 and vibration protection for thePCB 134 and its interface with the wires. Apotting grommet 142 is received over thePCB 134 for limiting the height of the potting material during assembly and curing. A cushion 133 (FIG. 17 ) is preferably located with thesensor tube 122 and surrounds thePCB 134 below thestop flange 138 for providing further protection against vibration and undesired forces that may otherwise be present on the PCB during shipping, installation and/or operation. Thesensor tube 122 can also contain other sensors besides liquid level, in particular temperature, which would provide information to the heating circuit for controlling circulation. Wiring connections and any circuitry required for the sensing is preferably located within the sensor tube and inside a sealed compartment above the mountinghead 114 and sensor tube connection. - Although a reed switch type probe has been shown and described, it will be understood that the present invention is not limited thereto. Other linear-type liquid level measurement sensors can be used, including but not limited to, capacitance, heated wire, ultrasonic, optical, pivoting float arm, and so on, as well as non-linear-type sensors such as resistance-type pivoting float arms.
- As best shown in
FIGS. 10 , 11 and 14-17, theheating unit 116 is preferably in the form of a single, elongate tube with afirst leg 144 and asecond leg 146 and a generallyU-shaped bend 148 extending therebetween. The first andsecond legs upper segments head 114. The upper ends of thesegments transducer 110, thesensor tube 122 is preferably securely connected to theheating tube 116. When the sensor tube and heating tube are constructed of metallic material, such as stainless steel, the parts are preferably welded together. However, it will be understood that the parts can be connected together through any well-known connection means, including but not limited to, adhesives, ultrasonic welding, mechanical fastening, and so on. - A substantial portion of the
fluid supply tube 118 is preferably connected to thefirst leg 144 of theheating tube 116 and thus spirals around the sensing probe therewith. However, it will be understood that thesupply tube 118 can alternatively be connected to thesecond leg 146. Thesupply tube 118 preferably includes a straightupper segment 154 that extends through the mountinghead 114. Thesupply tube 118 and returntube 120 are adapted for connection to a pump or the like in a well-known manner for delivering liquid from the tank (not shown) on which the transducer is mounted to a remote location and returning unused liquid back into the tank. - The extension of the fluid supply and return tubes into the tank can be inside of the
helical heating tube 116 or parallel on the same diameter. The fluid return tube does not have to extend far into the tank, but can if desired. Thesupply tube 118 preferably extends into the tank to the empty level inside the tank adjacent theU-shaped bend 148. If desired, a filter (not shown) can be located at the lower end of thesupply tube 118 inside the tank. - As shown in
FIGS. 10 and 18 , the helical configuration of theheating tube 116 is especially advantageous in that the helical coil can be made larger in diameter than the mounting head 114 (FIG. 10 ) and the opening 156 (FIG. 18 ) in thetank wall 158 to which thetransducer 110 is mounted. As shown inFIG. 18 , the major or outside diameter C of theheating tube 116 is larger than the diameter A of thetank opening 156, which is in turn larger than the minor or inside diameter B of theheating tube 116. By way of example, and in accordance with a preferred embodiment of the invention, the maximum major diameter C can be calculated as follows: -
C=A+(A−B) - For a 5-inch tank opening A and a 2.5-inch minor diameter B, the major diameter C of the
heating tube 116 is approximately 7.5 inches, a significantly larger heating tube area that the contents of the tank will be exposed to over prior art solutions. - As shown in
FIG. 10 , the distance or spacing 160 between adjacent coils is preferably greater than a thickness of the tank wall 158 (FIG. 18 ) to which thetransducer 110 will be mounted so that the thickness of the tank wall at thetank opening 156 can be cleared during the installation process. In this manner, thetransducer 110 can be screwed into atank opening 156, preferably with the float lifted to the upper portion of thesensing tube 122 just below the mountinghead 114, with the tank opening being much smaller in diameter than the outside diameter of the coils of the helically-shapedheating tube 116. With a larger diameter helically-shapedheating tube 116, the amount of heater tubing surface area installed in the tank is significantly increased. When the coil carries warm fluid, such as engine coolant, the heat transferring from the coil is used to thaw or prevent freezing of the tank contents surrounding the sensor as well as the supply and return tubes. Increasing the amount of surface area of the heater tubing increases the amount of heat transfer in a given amount of time. This reduces the potential for freezing of the tank contents in the area of the sensor and supply tubes at lower temperatures and causes quicker thawing of the contents at a given temperature than if the coils of theheating tube 116 were constructed with a smaller diameter. - Referring now to
FIG. 19 , aliquid level transducer 180 in accordance with yet another embodiment of the invention is illustrated. Theliquid level transducer 180 preferably extends into acontainer 11 and preferably includes a mountinghead 14, anelongate sensing probe 12 extending through the mountinghead 14 and downwardly therefrom with afloat 30 movable along the length of theprobe 12 as previously described, a first orinner heating unit 16 extending through the mountinghead 14 and bending around thesensing probe 12, a second orouter heating unit 116 spiraling around theinner heating unit 16 and afluid supply tube 18 extending through the mountinghead 14 and along a substantial length of theheating unit 16. The inner and outer heating units are similar in construction to the heating units previously described, with theinner heating unit 16 being sized to slip through the tank opening and theouter heating unit 116 having an outer diameter, as previously described, that is larger than the tank opening so that theliquid level transducer 180 turned or twisted through the tank opening to install the transducer in the tank. With this arrangement, the inner and outer heating units provide more surface area for thawing or warming the fluid to be measured at an increased rate without increasing the overall size of the liquid level transducer so that it can fit within a standard tank opening. - Referring now to
FIGS. 20 and 21 , a lower portion of aliquid level transducer 190 in accordance with a further embodiment of the invention is illustrated. Theliquid level transducer 190 preferably includes asensor tube 192 located within a heating unit which preferably includes an inner heatingfluid return tube 194 which is in turn located within an outer heatingfluid supply tube 196. Thesensor tube 192 is preferably connected to theouter supply tube 196 via aconnector 198 that preferably includes ahub 200 that preferably encircles and connects to theinner return tube 194 andspokes 202 that extend radially outwardly from thehub 200 and connect to theouter supply tube 196. Alower end 204 of theouter supply tube 196 preferably tapers toward thesensor tube 192 to create aninternal chamber 206 that communicates with both the inner return tube and outer supply tube. In operation, heating fluid from a fluid source (not shown) such as previously described, is directed down into theouter supply tube 196, as shown byarrows 208, to thereby heat the outer tube and the contents within the tank in the vicinity of the outer tube, and then up into theinner return tube 194, as shown byarrows transducer 190. It will be understood that theinner tube 194 can alternatively receive heating fluid and theouter tube 196 can function as the fluid return conduit without departing from the spirit and scope of the invention. - The
inner return tube 194 and/orouter supply tube 196 can be constructed of stiff or flexible material. In accordance with one preferred embodiment of the invention, theinner tube 194 is constructed of a flexible material that is compatible to the heating fluid such as rubber, polyurethane, vinyl, and so on, while theouter tube 196 is constructed of a more rigid or stiff material such as stainless steel, aluminum, other metals, and so on. However, it will be understood that the inner and outer tubes can be constructed of any suitable materials without departing from the spirit and scope of the invention. - The
sensor tube 192 preferably houses a liquid level probe such as a reed-switch-type probe as previously shown and described. However, it will be understood that the present invention is not limited thereto as other linear-type liquid level measurement sensors can be used, including but not limited to, capacitance, heated wire, ultrasonic, optical, and so on, as well as non-linear-type sensors such as resistance-type pivoting float arms - Referring now to
FIGS. 22 and 23 , aliquid level transducer 220 in accordance with yet another embodiment of the invention is illustrated. Thetransducer 220 preferably includes a mountinghead 222, anelongate sensing probe 224 extending through the mountinghead 114 and downwardly therefrom, and a helically-shapedheating unit 226 extending through the mountinghead 222 and spiraling around thesensing probe 224. - The
sensing probe 224 is preferably similar in construction to thesensing probe 112 withfloat 130 as previously described. Theheating unit 226 preferably includes an inner heatingfluid return tube 228 located within an outer heatingfluid supply tube 230. Theinner tube 228 is preferably constructed of a flexible material that is compatible to the heating fluid such as rubber, polyurethane, vinyl, and so on, while theouter tube 230 is constructed of a more rigid or stiff material such as stainless steel, aluminum or other metals, so that theheating unit 226 can be shaped in a quick and easy manner during manufacture through simple bending operations. Alower end 231 of the outer heating unit is sealed so that the heating fluid remains in the heating unit during use. Theheating unit 226 in this embodiment is easier to manufacture and requires less material than the spiral heating tube previously described with reference toFIGS. 10 and 19 since the heating unit does not need to spiral back up as in the previous embodiments. As described in theFIG. 19 embodiment, theinner tube 228 of the present embodiment can alternatively receive heating fluid and theouter tube 230 can function as the fluid return conduit without departing from the spirit and scope of the invention. - In accordance with one preferred embodiment of the invention, the
heating unit 226 has an outer diameter that is larger than the tank opening, as previously described with respect toFIG. 18 . In accordance with another preferred embodiment of the invention, theheating unit 226 has an outer diameter that is smaller than the tank opening so that theliquid level transducer 220 can be installed straight into the tank without the need to twist the transducer. -
Rods head 222 and alower base member 236 to provide added support to theliquid level transducer 220. - It will be understood that the term “preferably” as used throughout the specification refers to one or more exemplary embodiments of the invention and therefore is not to be interpreted in any limiting sense.
- It will be further understood that the term “connect” and its derivatives refers to two or more parts capable of being attached together either directly or indirectly through one or more intermediate members. In addition, terms of orientation and/or position as may be used throughout the specification denote relative, rather than absolute orientations and/or positions.
- It will be further understood that terms of orientation and/or position as may be used throughout the specification, such as upper and lower, horizontal and vertical, inner and outer, and so on, refer to relative rather than absolute orientations and/or positions.
- It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
Claims (19)
1. A transducer for determining the level of contents within a container wherein the contents are subjected to at least partial solidification at or below a freezing temperature, the transducer comprising:
a mounting head adapted for connection to the container;
a liquid level sensor adapted to extend into the container from the mounting head; and
a spiral-shaped heating unit comprising a first elongate tube extending through the mounting head and being formed with at least one coil that surrounds at least a portion of the liquid level sensor, the elongate tube being adapted to circulate heating fluid therein to thereby heat the contents of the container at least in the vicinity of the liquid level sensor.
2. A transducer according to claim 1 , wherein the tank has an opening with a first diameter and the coil has a second diameter that is larger than the first diameter, such that the spiral-shaped heating unit is screwed into the tank opening during installation.
3. A transducer according to claim 2 , wherein the outside diameter is equal to C=A+(A−B), where C is the outside diameter of the coil, A is the diameter of the tank opening, and B is the inside diameter of the coil.
4. A transducer according to claim 2 , wherein the heating unit comprises a second elongate tube located within the first elongate tube, the first and second elongate tubes being in fluid communication such that heating fluid is adapted to flow from one of the first and second elongate tubes to the other of the first and second elongate tubes.
5. A transducer according to claim 1 , wherein the heating unit comprises a second elongate tube located within the first elongate tube, the first and second elongate tubes being in fluid communication such that heating fluid is adapted to flow from one of the first and second elongate tubes to the other of the first and second elongate tubes.
7. A transducer according to claim 1 , and further comprising a fluid supply tube extending through the mounting head, the fluid supply tube extending along the at least one coil of the heating tube to thereby heat the fluid supply tube.
8. A transducer according to claim 7 , wherein the liquid level sensor comprises a sensing tube extending through the at least one coil.
9. A transducer according to claim 8 , wherein the sensing tube and at least one coil are connected together for structural stability.
10. A transducer according to claim 1 , wherein the at least one coil comprises a plurality of coils.
11. A transducer according to claim 10 , wherein the first elongate tube is bent and a lower end thereof to thereby create a coiled supply tube segment and a coiled return tube segment, the supply and return tubes extending adjacent to each other.
12. A transducer according to claim 1 , and further comprising a second heating unit surrounding the first heating unit, the second heating unit comprising:
a second heating tube extending through the mounting head and having:
first and second upright segments connected via a first lower bend;
a third upright segment connected to the second upright segment via an upper bend; and
a fourth upright segment connected to the third upright segment via a second lower bend;
the first and fourth upright segments being adapted for fluid connection to a fluent heating source for heating the contents of the container.
13. A transducer for determining liquid level within a container having an opening with a first diameter, the transducer comprising:
a mounting head adapted for connection to the container;
a liquid level sensor adapted for extending into the container from the mounting head; and
a heating tube extending through the mounting head and having:
first and second upright segments connected via a first lower bend;
a third upright segment connected to the second upright segment via an upper bend; and
a fourth upright segment connected to the third upright segment via a second lower bend;
the first and fourth upright segments being adapted for fluid connection to a fluent heating source for heating the contents of the container.
14. A transducer according to claim 13 , and further comprising a fluid supply tube extending through the mounting head and into a space created by the first through fourth upright segments of the heating tube, wherein the fluid supply tube extends adjacent to at least one of the heating tube segments to thereby heat the fluid supply tube.
15. A transducer according to claim 14 , wherein the liquid level sensor comprises a sensing tube extending into the space.
16. A transducer according to claim 15 , wherein the sensing tube and the heating tube are connected together for structural stability.
17. A transducer for determining the level of contents within a container wherein the contents are subjected to at least partial solidification at or below a freezing temperature, the transducer comprising:
a mounting head adapted for connection to the container;
a liquid level sensor adapted for extending into the container from the mounting head; and
a heating unit extending through the mounting head and into the container, the heating unit having an outer tube and an inner tube extending inside and along a length of the outer tube, the outer and inner tubes being in fluid communication such that heating fluid is adapted to flow from one of the outer and inner tubes to the other of the outer and inner tubes to thereby heat the contents of the container.
18. A transducer according to claim 17 , wherein the liquid level sensor comprises a sensing tube located within the inner tube.
19. A transducer according to claim 18 , wherein the inner, outer and sensing tubes extend linearly into the container from the mounting head.
20. A transducer according to claim 17 , wherein the heating unit spirals around the liquid level sensor.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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US13/100,975 US20110271754A1 (en) | 2010-05-04 | 2011-05-04 | Liquid Level Transducer with Heating Unit |
PCT/US2012/036461 WO2012151469A1 (en) | 2011-05-04 | 2012-05-04 | Liquid level transducer with heating unit |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US33096910P | 2010-05-04 | 2010-05-04 | |
US13/100,975 US20110271754A1 (en) | 2010-05-04 | 2011-05-04 | Liquid Level Transducer with Heating Unit |
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US20110271754A1 true US20110271754A1 (en) | 2011-11-10 |
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US13/100,975 Abandoned US20110271754A1 (en) | 2010-05-04 | 2011-05-04 | Liquid Level Transducer with Heating Unit |
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WO (1) | WO2012151469A1 (en) |
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US20130125997A1 (en) * | 2011-11-18 | 2013-05-23 | Ford Global Technologies, Llc | Methods for an exhaust fluid level sensor |
DE102012001580A1 (en) * | 2012-01-27 | 2013-08-01 | Daimler Ag | Method for determining filling volume of usage liquid in storage tank of motor vehicle, involves detecting signal of fluid level sensor arranged in storage tank, where ultrasonic sensor is used as fluid level sensor |
US20140020464A1 (en) * | 2012-01-17 | 2014-01-23 | Texas Lfp, Llc | Liquid Level Transducer with Isolated Sensor |
US20140202142A1 (en) * | 2013-01-18 | 2014-07-24 | Cnh America Llc | Diesel exhaust fluid tank for an off-road vehicle |
US20150153215A1 (en) * | 2013-12-03 | 2015-06-04 | Aai Corporation | Level Sensing Device |
US20150251893A1 (en) * | 2012-09-25 | 2015-09-10 | Volvo Construction Equipment Ab | Arrangement, a method and a computer program for controlling filling of a tank |
CN104913827A (en) * | 2015-06-29 | 2015-09-16 | 铁岭兴科精密仪器有限责任公司 | An anti-freezing liquid level meter |
US20150377112A1 (en) * | 2014-01-08 | 2015-12-31 | Komatsu Ltd. | Reducing agent tank and work vehicle |
US20170138826A1 (en) * | 2015-11-16 | 2017-05-18 | Wema System As | Debubbling Sleeve For Fluid Sensors and Sensor Systems Comprising Same |
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